1. Field
This invention pertains to sight assemblies for use with archery bows. It is particularly directed to such assemblies which utilize rotatable elements to adjust the vertical position of illuminated sight pins.
2. State of the Art
Aiming sights of various designs are commonly used in the sport of archery. Such sights typically comprise an assembly, which includes a bracket supported by structure fixed to the handle riser of the bow. With the bow held in its normal position of use, its limbs are considered to be oriented approximately vertically. References in this disclosure to xe2x80x9cverticalxe2x80x9d or xe2x80x9chorizontalxe2x80x9d orientations are with reference to such vertical bow limbs. The sight bracket generally supports a plurality of vertically spaced sighting elements (often called xe2x80x9cpinsxe2x80x9d), each of which extends approximately horizontally to terminate in an end (sometimes called a xe2x80x9csighting beadxe2x80x9d) near a vertical sight plane. Each sight element corresponds to a distinct target distance, depending upon its precise vertical position along the sight plane.
Various mechanisms have been relied upon to adjust the horizontal position of the sight plane or the sight beads. Such adjustments are advantageous to account for the influence of wind and/or the shooting idiosyncrasies of individuals, and are commonly referred to as xe2x80x9cwindage adjustments.xe2x80x9d Similarly, various mechanisms have been utilized to adjust the vertical positions of the respective sight elements. Such adjustments are commonly referred to as xe2x80x9cdistance adjustments.xe2x80x9d One class of mechanisms for providing distance adjustment capability mounts individual pins in an assembly which translates rotation of a knob into vertical linear motion, up or down. This arrangement is particularly advantageous, providing for infinite and stable adjustability superior to most other arrangements.
Representative of this class is the sighting assembly disclosed by U.S. Pat. No. 4,449,303, the disclosure of which is incorporated as a portion of this disclosure. The sighting elements of that assembly comprise pins individually threaded into a central bore of a cylindrical carriage element. Each carriage element is adjustable up and down within a particular slot of a bracket in a rack-and-pinion type of engagement. The carriage element has a knob portion and a pinion portion. The pinion portion engages a rack element within the slot. Rotation of the knob is thus translated into vertical adjustment, without affecting the horizontal (windage) adjustment of the sighting bead. Windage adjustment is made by turning individual pins within their respective cylindrical elements. In this construction, the pins inherently rotate during any adjustment of either elevation or windage. Because the pins are cylindrical, this rotation is immaterial to the functioning of the sight.
Both target shooting and hunting are frequently practiced under low light conditions in which visibility of the sight element becomes poor. There has thus evolved a variety of sight assemblies structured to gather ambient light to illuminate the sight beads. This light gathering function is generally performed by special plastic or glass elements. Notable among these light gathering/transmitting elements are fiber optic strands. U.S. Pat. Nos. 5,442,861; 5,201,124; 5,168,631 and 4,928,394, the disclosures of which are incorporated as a portion of this disclosure, identify a number of light gathering elements and sighting pin structures incorporating those elements. Incorporation of these elements in sight systems in which the pins rotate during either windage or distance adjustments has not been feasible, however, because of the necessity for the light gathering elements to remain in a fixed rotational orientation. This design constraint is particularly significant in the case of fiber optic strands.
This invention provides a sight assembly for archery bows which is constructed to translate rotation of an adjustment knob into linear travel of a sighting pin, without rotating the pin. It is thereby feasible for the sighting pins to carry a light gathering element, including a fiber optic element. Preferred versions of the assembly provide for infinite windage adjustment of the sighting plane, also without rotating the sighting pins. Other embodiments provide a pin assembly wherein an adjustment knob is associated with a locking mechanism. In preferred arrangements, both the adjusting knob and the locking mechanism are structured for operation by a simple tool comprising an element of the sight assembly.
While this invention is described with primary focus upon rack and pinion arrangements, it is recognized that many alternative mechanical expedients are available to translate the rotation of an adjustment knob into linear motion of a sight pin. For example, a cylindrical element may be substituted for the pinion and a smooth slot may be substituted for the rack in the arrangements disclosed by the ""303 patent. Frictional engagement of these substituted elements provides the same translation of knob rotation to linear pin travel, but in a less positive fashion. The improvement of this invention is broadly applicable to any structure operative to provide linear vertical movement of a sight pin in response to rotational movement of an adjustment fixture, such as a screw or knob.
Similarly, the windage adjustment feature of this invention may be provided by various mechanical arrangements. A screw thread assembly is generally preferred because of its simplicity and ease of manufacture and assembly. Any other mechanism capable of adjusting the position of the pins of the assembly along the horizontal sight plane without rotating the individual sight pins could be utilized. Among such arrangements are rack and pinion assemblies, belt drives, chain drives, piston drives and various fluid drive assemblies. It is even feasible to utilize a manually operable telescopic boom arrangement.
In a preferred embodiment of the invention, at least one mechanism is associated with the sight and operable to convert a rotatational user input into a purely translational output operable to adjust a component of the sight. A first preferred such mechanism is a windage adjustment mechanism operable simultaneously and uniformly to effect a horizontal adjustment of a plurality of sight pins. A second preferred such mechanism is an elevation adjustment mechanism operable to effect a vertical adjustment of at least one sight pin.
Preferred mechanisms generally include: a knob element adapted to receive rotational input from a user; a slide member configured and arranged in harmony with holding structure to resist rotation of the slide member and permit translational movement of the slide member with respect to the holding structure; and linkage structure between the knob and the slide member, with the linkage structure being operable to move the slide member responsive to rotation of the knob.
An operable elevation adjustment mechanism can include a plurality of sight pins carried on a base structure that is adapted for attachment, at a plurality of vertically disposed positions, to structure carried by a support arm of the sight assembly whereby to permit a simultaneous and uniform displacement of the pins in a vertical direction. One preferred elevation mechanism includes a pinion engaging a rack, with the pinion being operated by a driven interface adapted to receive a rotational driving input from a user effective to change a vertical position of a sight pin with respect to the sight. Since the sight pins do not rotate during their adjustment in elevation, it is feasible to dispose a light gathering element in association with a sight pin for purely vertical translation between first and second elevations.
It generally is desirable also to include a lock adapted to resist changes in the vertical position of the pin in an elevation mechanism. Such a lock can be operated by a lock interface that is adapted to receive rotational locking and unlocking input from a user. A convenient tool to make adjustments to a sight includes a wrench adapted on a first end to apply a rotational input to a lock interface. Ideally, the wrench will be adapted on a second end to apply a rotational input to a driven interface to effect an adjustment of a sight component. Some sights further include storage structure adapted to hold such a wrench in a snap-fit engagement.